The present invention relates to a yarn accumulator with a rotary drive means and with an accumulator roller drivable by this rotary drive means, having a feed end to which the yarn is feedable substantially tangentially from a feed station. The accumulator roller includes an exit end from which the yarn is dischargeable counter to the action of a restraining element through a yarn guide means arranged in prolongation of the axis of the accumulator roller.
Such yarn accumulators are known in a wide variety of constructions (German Offenlegungsschriften Nos. 2,555,802 and 2,607,460). In these cases, the yarn is always fed tangentially to the accumulator roller, wraps the latter a plurality of times and leaves the accumulator surface in an axial direction between the accumulator roller and a brake ring placed on the exit end of the latter, for which purpose the yarn must be passed through an annular yarn guide. Such yarn accumulators are used in yarn-processing machines such as various types of knitting machines and weaving looms (German Offenlegungsschrift No. 2,555,802), but also in yarn-producing machines, particularly open-end spinning machines (German Offenlegungsschriften Nos. 2,553,892 and 2,717,314). These known apparatuses have the common disadvantage that the yarn must be threaded in a complicated manner into the brake ring and into the yarn guide. This is time-consuming and demands a stationary arrangement of the yarn accumulator even if an accumulation is only required temporarily.
It is, therefore, an important object of the present invention to produce a yarn accumulator which makes it possible to apply the yarn to the yarn accumulator in a simple manner.
Another object of the invention is to develop the yarn accumulator further so that it can be moved into the yarn path and accumulate the yarn only temporarily without interrupting the yarn path.
Yet another object of the present invention is to produce a device to measure the yarn length accumulated on an accumulator roller which operates with high precision and is of simple construction.